The IRT HDT-4611 and HDR-4611 are transmit
and receive modules designed principally for use as a SMPTE292M 1.485 Gb/s
serial digital video fibre optic transmission link, using 9/125µm single
mode fibre for path lengths with path attenuation of 5- 31dB. This enables
the use of space saving fibre optic cable for reliable transmission of
digital video signals over lengths greater than can be provided with coaxial
cable. The transmit / receive system specifications apply to all signal
conditions, including the SMPTE292M pathalogical test sequence.
The HDT-4611 transmitter features an input circuit with automatic cable
equalisation for Belden 8281 (or equivalent) coaxial cable followed by a
plug in laser transmitter.
The HDR-4611 receiver uses a plug in APD detector preamplifier module,
signal conditioning and a reclocking circuit for the 1.485 Gb/s data rate,
or for 270 Mb/s SDI and ASI signals. Two in phase serial digital outputs are
provided from the transmission link on the rear assembly.
On the HDT-4611 transmitter LED indicators
on the front panel indicate the presence of signal, loss of laser power and
presence of DC power. Relay contact outputs for remote indication will
indicate failure of the laser operation, loss of input signal, and loss of
On the HDR-4611 receiver LED indicators on the front panel indicate PLL lock
at 1.485 Gb/s or 270 Mb/s operation, locked signal presence, optical input
failure, and presence of DC power. Relay contact outputs for remote
indication will indicate loss of signal, loss of optical input, and loss of
An optional SNMP (Simple Network Management Protocol) plug-in module is
available, for each unit, for remote monitoring when used in conjunction
with IRT's 4000 series frame fitted with SNMP capability.
The HDT-4611 and HDR-4611 are Eurocard modules designed to fit IRT's
standard Eurocard frames as well as IRT's 4000 series frames for use with
IRT's SNMP system and may be used alongside any other of IRTs analogue or